INTRODUCTION TO PING.

Ping is a common and initial step for troubleshooting the problem in networking world. Ping tool tests TCP/IP network connectivity. It sends ICMP echo request messages to the host and expecting a reply. The destination host has to send a reply back to the sending host within a predetermined time. Ping sends a packet of 64 bytes (56=data+8=header). Echo request are send approximately after one second. It is also used to test the network interface card.

It gives us the following information.

Remote host is alive or dead.

Round trip time (time from sending to receive packet).

Packet loss percentage.

(Note: ping tool test the reachability at the IP layer but the firewall and access list can be a blocker)